Facebook scored an initial legal victory in its IPO case following a federal judge's dismissal of a group of investor lawsuits filed against the company.

More than 30 lawsuits were filed against Facebook after it went public last May, alleging that the company shared business information with analysts who then shared the information with large institutional investors without disclosing it to the wider investing public.

Facebook, however, did make "extensive warnings" in its registration statement, drafts of the registration statement and in its final IPO documents about the health of its business tied to mobile trends, according to a ruling filed Wednesday in the U.S. Court for the Southern District of New York.

"Even if internal projections could be considered material to the IPO, [the plaintiffs] have not demonstrated that the Facebook projections would have 'significantly altered the total mix of information in the marketplace,' considering that these disclosures were publicly disseminated," the ruling said.

"Based upon our experience in the second quarter of 2012, to date, the trend we saw in the first quarter of [daily active users] increasing more rapidly than the increase in number of ads delivered has continued," Facebook said in its registration statement filed May 16 with the U.S. Securities and Exchange Commission, two days prior to its IPO.

The social network has come under pressure to increase its revenue as users flock to mobile devices, but advertisers maintain a stronger presence on the desktop. The company reported during its fourth-quarter earnings call that the number of daily mobile users had exceeded daily Web users for the first time ever, though its mobile business constitutes 23% of its total advertising revenue.

Wednesday's ruling addressed the first several IPO lawsuits, which have been classified as derivatives cases. The judge has yet to rule on the remaining class-action securities lawsuits, but Wednesday's ruling addresses the same core allegation related to disclosures.

Basically, the ruling shows that "companies don't have a duty to disclose their projections as part of their written IPO documents," said Facebook attorney Richard Bernstein. "The law has rejected for decades the contrary argument that Facebook plaintiffs have made," he said.

Plaintiffs have 20 days to replead the case. A briefing for the remaining IPO cases will be completed in mid-July; a decision is expected later in the fall.